It is well known in the art of radiation therapy to position a patient in the "frogleg" position for radiation therapy to be performed at the pelvic region. In the frogleg position, the patient lies on his back with his/her legs bent at the knees and spread apart and with the bottoms of the feet touching each other. This frogleg position is characterized also by the raised knees. This position is so beneficial in radiation therapy, because it decreases the amount of skin folds at or near the treatment field and places as much of the femur as possible out of the treatment area. One of the problems in positioning a patient in the frogleg position is that it is difficult to obtain a consistent frogleg position from the patient because the legs must be held spread apart while being bent at the knees and with the feet touching each other. Another problem is that it is difficult to stabilize the patient in the desired position throughout the duration of the radiation therapy treatment. Finally, repeatability is important in radiation therapy where multiple treatments are common. It is difficult to position a patient in a repeatable position over multiple radiation treatments.
Several prior art references teach abduction devices that may be fitted on patients with various orthopedic conditions. See U.S. Pat. Nos. 5,558,628; 5,362,305 and 1,230,512. Devices for accomplishing simple leg abduction, however, are not acceptable in creating the frogleg position for radiation therapy. The knees must also be elevated to be most effective in radiation therapy.